An aircraft-borne chemical ionization – ion trap mass spectrometer (CI-ITMS) for fast PAN and PPN measurements

Abstract

Abstract. An airborne chemical ionization ion trap mass spectrometer instrument (CI-ITMS) has been developed for tropospheric and stratospheric fast in-situ measurements of PAN (peroxyacetyl nitrate) and PPN (peroxypropionyl nitrate). The first scientific deployment of the FASTPEX instrument (FASTPEX = Fast Measurement of Peroxyacyl nitrates) took place in the Arctic during 18 missions aboard the DLR research aircraft Falcon, within the framework of the POLARCAT-GRACE campaign in the summer of 2008. The FASTPEX instrument is described and characteristic properties of the employed ion trap mass spectrometer are discussed. Atmospheric data obtained at altitudes of up to ∼ 12 km are presented, from the boundary layer to the lowermost stratosphere. Data were sampled with a time resolution of 2 s and a 2σ detection limit of 25 pmol mol −1 . An isotopically labelled standard was used for a permanent on-line calibration. For this reason the accuracy of the PAN measurements is better than ±10% for mixing ratios greater than 200 pmol mol −1 . PAN mixing ratios in the summer Arctic troposphere were in the order of a few hundred pmol mol −1 and generally correlated well with CO. In the Arctic boundary layer and lowermost stratosphere smaller PAN mixing ratios were observed due to a combination of missing local sources of PAN precursor gases and efficient removal processes (thermolysis/photolysis). PPN, the second most abundant PAN homologue, was measured simultaneously. Observed PPN/PAN ratios range between ∼0.03 and 0.3.

Potential of airborne lidar measurements for cirrus cloud studies

“…This gave us the opportunity to perform measurements in cloudy and in cloud-free air masses. HALO was equipped with a spectrometer system operated by University of Leipzig together with an instrument for measuring the actinic flux in cooperation with Forschungszentrum Jülich (HALO-SR) (Fricke et al, 2014), an automated high-volume air sampling system (MIRAH -Measurements of Stable Isotope Ratios in Atmospheric Trace Gases on HALO) of University of Wuppertal (Krebsbach et al, 2013), and an ion trap mass spectrometer of DLR (Roiger et al, 2011). Additionally, and in the focus of this paper, the DIAL system WALES (Wirth et al, 2009) was provided by DLR Institute of Atmospheric Physics (IPA).…”

Peroxyacetyl nitrate (PAN) and peroxyacetic acid (PAA) measurements by iodide chemical ionisation mass spectrometry: first analysis of results in the boreal forest and implications for the measurement of PAN fluxes

“…This technique has been used to make measurements with high sensitivity and at high time resolution LaFranchi et al, 2010;Roiger et al, 2011) e.g. for use in eddy correlation studies of PAN deposition (Turnipseed et al, 2006;Wolfe et al, 2009).…”

Characterization of a thermal decomposition chemical ionization mass spectrometer for the measurement of peroxy acyl nitrates (PANs) in the atmosphere

“…Because of its robustness, and its proven track record for aircraft and ground measurements conducted over the last few years both with our instrument and others (Roiger et al, 2011), we have used this photolytic cell as the benchmark for the rest of the calibrations in this work. However, the generation of other PANs with the same photolytic mechanism is not very straightforward.…”

“…An in-situ calibration system using an isotope labeled photolytic source (Flocke et al, 2005;Roiger et al, 2011) is integrated into this system. This photolytic source has been extensively modified for aircraft use compared to the design available commercially (Metcon, Inc.) and has been thoroughly described by Flocke et al (2005).…”